There are provided a plurality of methods for detecting a scene change in a streamed video, the streamed video comprising a series of pictures. An example method comprises calculating, for a plurality of positions, a difference between the costs of coding macro-blocks at the same position in successive pictures. The method further comprises identifying a new scene when the sum of the differences for a plurality of positions meets a threshold criterion. There is further provided a method of determining the perceptual impact of a packet loss on a streamed video the method comprising: identifying a packet loss; and determining if the lost packet contained information relating to a picture at the start of a new scene, wherein a new scene is detected using one of the methods disclosed herein.